Our objective is to provide information useful in selection of the optimal method of revascularization for patients with coronary artery disease. Patients from twelve clinical centers with significant coronary disease documented at cardiac catheterization will be considered for enrollment in the study. A panel of expert angiographers and surgeons will review each patient's film to determine whether the patient is a candidate for percutaneous transluminal coronary angioplasty (PTCA) and for coronary artery bypass grafting (CABG). Eligible patients that provide informed consent will be randomized to receive either PTCA or CABG. Only patients with significant (Canadian Class III or IV) symptoms on medical therapy will be entered into the trial unless they have evidence of prognostically important exercise-induced ischemia. Patients with left main disease or vessels that are not suitable for PTCA will be excluded from the randomized trial. At Duke, an estimated 250 patients will be eligible for the trial each year. Overall, the trial will enroll 2,000 patients. All patients will be followed for at least 4 years. The primary study endpoints will be mortality, nonfatal infarction, and rest and exercise left ventricular function. In addition, detailed information concerning functional status, employment, psychological well-being and cost will be collected on all randomized patients. Power analyses suggest that these end-points may be the most sensitive to differences in outcome between PTCA and CABG. Patients who are eligible for both revascularization procedures and are not randomized will be entered into a registry, and baseline and follow-up information will be collected on them. Results of this investigation are anticipated to enhance greatly the management of patients with coronary artery disease.